


a birthday to remember

by lightofthewind



Category: Free!
Genre: Birthday Presents, Canon Compliant, Gen, Light Angst, Matsuoka Rin's Birthday, Meeting in secret, Sibling Bonding, Surprise Planning, Swimming, a lot of liberties were taken but i tried my best to keep it, set during rin's time at iwatobi elementary
Language: English
Status: Completed
Published: 2016-02-23
Updated: 2016-02-23
Packaged: 2018-05-21 16:01:00
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,166
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6057520
Author URL: https://archiveofourown.org/users/lightofthewind/pseuds/lightofthewind
Summary: <blockquote class="userstuff">
              <p>In which Rin is off to Iwatobi, Sousuke is left angsting in the aftermath and a new Sano trio is formed when Kou enlists the boys' help with a surprise birthday present.</p>
            </blockquote>





	a birthday to remember

**Author's Note:**

  * For [ohbecalm](https://archiveofourown.org/users/ohbecalm/gifts).



> for the lovely ashe, whom I'm very glad to be friends with ❤️  
> consider this a belated birthday gift ^^  
> I hope you enjoy it!  
>   
> so  
> I actually wrote this back in the summer when we were rewatching free! but never got around to publishing it for some reason  
> then the other day I found it on my drafts, reread it again and didn't hate it, at least? one round of editing later and here we are  
> overall I'm satisfied with how it turned out ~  
> 

The hallway is brimming with students ready to leave after another long day of schoolwork.

Silently, Kisumi’s presence materializes by Sousuke’s side.

Ever since Rin’s departure to Iwatobi, this had become an usual sight. Perhaps in an effort to reclaim the sudden void that had solidified where memories of Rin’s previously constant company overlapped and help dispel such ghost traces the only way he knew how, Kisumi had begun to follow Sousuke around, wanting to spend more time together. He found it troublesome. The two of them had never been that close in the first place - and besides, Kisumi was being way too obvious about what his intentions were. Their interactions were strained by awkwardness and a tint of forcefulness. Deep down, Sousuke couldn’t help but feel grateful for the distraction it provided anyway.

Falling into step, they follow their classmates and head towards the exit.

“Sousuke- _kun_!” a small voice calls for him. Incidentally, it belongs to no one else but the only other person who might have been taking Rin’s absence harder than himself - Matsuoka Kou, Rin’s little sister.

Bidding farewell to Kisumi, who nevertheless promises to be waiting for him by the gate when he’s done, Sousuke approaches her.

“Kou!... Is there something you need?”

It was rather strange seeing the girl all by herself. Even if both siblings attended the same school, Rin had always kept his distance, making sure they ran in different circles. Kou had thus forged her own separate friendships, and nowadays it was rare to spot her without a group of loud, animated girls tagging along.

If it weren’t for that - or the fact that Sousuke liked to avoid talking about his feelings unless explicitly necessary and after a long period of denial and internally dissecting them - Sousuke might have tried to approach Kou himself before.

Kou stops fidgeting with her hands, having gathered herself through this self-reassuring, short-lived gesture and, face full of determination, digs right in.

“Sousuke- _kun_ … I need a favour from you.”

 

* * *

 

Kou had been planning this ever since Rin had announced his decision to leave for Australia. It would be Rin’s last birthday spent with his family - his last birthday spent with Kou. It needed to be special, the absolute best! Maybe if Kou could make it memorable enough, Rin would even change his mind and realize he didn’t really need to leave after all.

Step one was, of course, guaranteeing Sousuke- _kun_ ’s participation. It was a bit tricky, because Kou had never approached Sousuke- _kun_ on her own. They had spent a lot of time together recently - Sousuke had visited and spent Christmas at their place while Rin was down with the flu; and afterwards, had even showed up for a repeat performance on New Year’s when it was Kou the one at the sickbed and in need of cheering up - but never without Rin there as a mediator. Granted, since Rin was still the whole reason behind this meeting, it definitely made things easier, but Sousuke- _kun_ could be quite an intimidating boy sometimes and Kou couldn’t help but feel a little nervous.

When she first explained to him what her plan entailed, Sousuke- _kun_ ’s face displayed a slightly shocked reaction. It was only there for a second, though, before being replaced with a wide grin and a thoughtful stare, which Kou took to mean Sousuke- _kun_ was in and already thinking up how to best tackle every potential obstacle to her plan being put in practice.

After successfully completing the first step, everything else came together a lot easier than Kou had expected at first, in no small part thanks to Kisumi- _kun_ , whom Sousuke had convinced into helping (or maybe it was the other way around, and Kisumi had been the one convincing Sousuke his help was in fact needed? Kou didn’t know Kisumi as well as she did Sousuke, but he gave off the impression of being a very intuitive and forward person. If you asked her, he also seemed genuinely committed to Sousuke- _kun_ ’s happiness. And anyone could see that ever since the day Kou recruited him into her plan, Sousuke- _kun_ was indeed livelier).

Personally, Kou doesn’t really want to know how Kisumi- _kun_ managed it - it couldn’t have been without resorting to less than perfectly clean methods, and Kou was young but she was already quite familiar with the notion of plausible deniability - but here they are, the three of them holding the set of keys to Sano SC and in the midst of trespassing. Even if they are caught and end up in prison, Kou is sure it’d make Rin’s tenth birthday celebration an unforgettable event, so it would without a doubt still be worth it in the end.

“I’ll be on the lookout, so the both of you can do your swimming thing with no worries!” promises Kisumi, before shoving Kou and Sousuke inside. That boy sure is gutsy.

It’s not that Kou is starting to regret her brilliant idea, because she isn’t, but in hindsight, maybe they could’ve gone about it in a different way. Something on a lesser scale, for certain.

She feels a comforting hand on hers and lets herself be tugged away in the pool’s direction. “Don’t worry, Kou. This is our adventure! Plus, it’s for Rin’s sake, right?”

Her worries put to rest and a smile on her face, Kou nods.

 

Kou pulls off her clothes, revealing her swimsuit underneath. She gets closer to the pool, and dives in. Sousuke follows.

He gets an older, stern look in his eyes - trying to look like a teacher, probably - and turns to Kou. “OK. It’s like we’ve discussed. You know how to float and you know the basics of each stroke, right? Now you just need to practice and I’ll correct your form. You can trust me, Kou. You can do this.”

 _Sousuke-_ kun _is so reliable._ Onii-chan _is very lucky to be friends with him._

“First, let’s start with breast.”

 

* * *

 

One hour is over before they know it and Kisumi shows up to call them back. The three of them need to get home, before any of their parents get suspicious. Today Kou finally learned how to swim properly, without the help of water wings or kickboards. She can do the breaststroke, all on her own! It’s enough to surprise _onii-chan_ already, but now that she knows for sure that she can do this, she’s feeling greedy. You have to aim high, right?

“Sousuke- _kun_.” Kou calls out, on the way home.

“You want to do it again, right? Try the other strokes too?” Sousuke- _kun_ says, with a knowing look in his face.

“ _Hai_.” As an afterthought, Kou adds, “If it isn’t too much trouble for you.”

“Of course it isn’t too much trouble, Kou- _chan_!” reassures Kisumi. Conspirationally, he adds, “Sousuke would be doing nothing else but mope if it weren’t for this, you know.”

“Shut up, Kisumi.”

They end up going to Sano SC the whole week, an hour each day like the first time. Although Kou still has trouble with the backstroke (how is she supposed to know where the pool ends if she can’t see it?) and the butterfly (she feels burning hatred for whomever invented this stroke because why would anyone willingly want to swim in such an overly complicated and exhausting form? But Sousuke- _kun_ told her that Rin is one of the best at swimming butterfly in their age group, so Kou tries her hardest at it too), by the end of the week she can do the full individual relay and at least put up a decent show.

And just in time, since Rin’s birthday is already next week.

After thanking Sousuke and Kisumi properly (gifting them with a dumbbell each, so they can train and build their muscles and reap the results when they’re older - and with Kou there to see it, of course!), and an inward sigh of relief at not being caught even once (their criminal records will rest pristine for a little while longer), Kou calls Rin first thing after arriving home on Friday evening.

“What is it, Gou?” comes Rin’s drawl from the other side of the phone.

“ _Onii-chan_! You’re coming home for your birthday, aren’t you?”

“Yes. You know this already… I give you the exact same answer every single time you ask.”

“I’m just happy!! I miss you so much, _Onii-chan_! But now I’m going to see you! And spend the whole day with you! It’s less than one week away too!! _Onii-chan_ is going to be older... that’s not fair.”

“Hmph. It’s not my fault you’re still a kid, Gou.” There’s a instance of static noise before he adds in a small voice, “I also miss you. And _Okaa-san_.”

 

* * *

 

February 4th arrives at last. Kou is a bundle of nerves, because what if things go wrong? What if her form isn’t as good as when she practiced with Sousuke- _kun_? What if… Rin doesn’t care? Kou loves her brother with all her heart, and even if he acts nonchalantly about it most of the time, she knows Rin loves her just as much too. Still, there's always a little voice inside her head that wonders.

Her concerns are brushed aside as soon as Rin gets home, though. Their grandma’s here too, and Kou lets herself get lost in the celebrations. They sing happy birthday to Rin, and he blows off the ten candles with a satisfied grin on his face. His party hat almost falls from his head due to the enthusiastic strength and restless movements he opens his presents with. Kou gives him a dumbbell, the same brand as the ones she gave Sousuke- _kun_ and Kisumi- _kun_ for all their troubles. She thought they’d be here today too, but Rin insisted in making it a family-only celebration. He’s probably trying not to make it harder on them all, since he will be leaving again soon anyway, but Kou knows it’s not going to work like that. Sousuke- _kun_ and Kisumi- _kun_ also made her promise not to tell Rin about their contribution to her improvement. It was their only condition to help her, they said. Foolish boys, the three of them were.

When the celebration shows signs of slowing down, Kou pushes Rin aside. She’d okayed everything with her parents, who give her encouraging nods.

“ _Onii-chan_ , Kou has a surprise for you! Come with me!”

“A surprise? What kind of surprise?” Rin looks suspicious, but still lets himself be dragged by his little sister.

 

* * *

 

Rin didn’t know what to expect, but standing outside Sano SC was definitely not it.

“Kou? What are you up to?” he utters, raising his eyebrows.

“If _onii-chan_ is worried about meeting anyone he knows he doesn’t have to. At this time, there’s only the little kids here. I just have something to show you.”

Surprised he had been read so easily, Rin can’t find any words in reply, and ventures inside instead.

An employee takes notice of them.

“Rin- _kun_! Gou- _chan_! I spoke to your parents - Gou- _chan_ is here to try the SC out, right? Please go ahead!”

_Try the SC out? What was the meaning of this?_

“Kou is going to change really quickly, so wait for me here, okay, _onii-chan_?”

Kou disappears into the changing room and Rin is left dumbfounded. He doesn’t have to wait long. True to her word, Kou is back at his side, in a heartbeat. She drags him again, and they arrive at the pool.

Kou is starting to look a bit nervous now, but without another word she dives into the pool and starts to swim.

She… actually starts to swim. Kou had never been fond of swimming like her brother. She loved going to the water in the summer, but always with her floaty close behind. She would ask to go to all his swim meets, but she’s never wanted to join a swim club herself. And now… she is swimming!

Rin can’t help his enthusiasm. After swimming a full turn in a proficient breaststroke, Kou is back at her starting place and wears an innocent smile on her face. There's a slight blush on her face.

“What do you think, _onii-chan_?”

“Kou… You can swim!” Rin has tears running down his face. “You swim so well! How? Where did you learn this?”

Kou gets a mysterious smile on her face and changes the subject. “This isn’t all, you know? I can swim back and butter too!”

“ _What?_ ” Rin starts to cry harder and can only blurredly see Kou’s happy, grinning face before she assumes the backstroke pose and dives off.

But not without a parting remark: “ _Onii-chan_ ’s got another rival now! _Onii-chan_ should be careful or Kou’s going to be the one living up to the Matsuoka swimming legacy!”

At ten years old, Matsuoka Rin couldn’t have asked for a better birthday present, nor for a better little sister.


End file.
